Advantages of lithium ion rechargeable
battery

High energy density
Reduces the weight by half and volume by 20% to 50% compared to
the same capacity nickel-cadmium (Ni-Cd) and nickel-metal-hydride
(Ni-MH) battery.

High operating voltage

Reduces the number of battery required
since lithium ion battery can provide three times the voltage of nickel-cadmium
(Ni-Cd) and nickel-metal-hydride (Ni-MH) battery, which contributes
to miniaturization of electronic devices.

No memory effect

Unlike nickel-cadmium battery, lithium
ion battery have no "memory" effect, the effect which causes
charging capacity to be reduced by repeatedly charging and discharging
to insufficient levels, therefore, partial charging is possible.